Yeah that did cross my mind, the initial order was quite a chunk of money and I had a reply within a few hours.. I'll give the forum a try, thanks for the link.

Thanks, it certainly makes things easier! Worth taking the extra effort to make them properly, hopefully less head aches with setting them up knowing they are machined properly so the alignment between them should be good.

I replaced them both in the end, the old screw was cracked and it was an odd size. Also needed new bearings as well so just replaced the lot. Can't beat a bit of hard machining, sparks were disappointing though! It was actually worryingly not that hard if I'm honest... looked to be case hardened around 3mm per side, the rest was really soft...

I guessed it wasn't going to be amazing quality based on the price, think its was £30 for the screw and nut... we'll see how it does.